The present invention relates to designs, systems and methods of a light therapy device.
The concept of using light energy to treat human tissues has emerged in the last few decades. Radiation, UV, and broad spectrum light have all been employed therapeutically and efficaciously, enjoying wide acceptance in the medical community. One version of this, called Low Level Light Therapy (LLLT), uses a wide variety of wavelengths in the visible and near-infrared spectrum to generate a tissue response in a process that has become known as photobiomodulation. The potential list of applications for LLLT is enormous; everything from dental treatments to pain control and accelerated wound healing has been studied with promising results. Given the low incidence of side effects, ability to target specific tissues, and the relative ease of treatment, patient and physician acceptance and adoption of these technologies is justifiably growing.
The method of delivery has been problematic, however. Due to its coherent, single wavelength output and directionality, the laser diode is a commonly used light source, allowing practitioners to easily direct the beam to the target. Another potential source, the light emitting diode (LED), can also be used to generate light in a specific band of wavelengths, but with a much broader emission pattern. For completeness, we note that it is possible to generate either narrow or broad spectral ranges with a white light source and a filter. It has yet to be established whether narrow or broader emission spectra or coherent or incoherent light is more effective to induce photobiomodulation. The issue with all of the light sources is that human tissue, such as skin, can be highly reflecting. Furthermore, the presence of hair on the skin can cause significant absorption of the light intended for the skin. These two effects make it difficult to precisely control dosing during therapeutic applications. Since light can be scattered, absorbed, transmitted, or reflected, the light applied during certain LLLT applications should either be on the surface of the target, or be very close to be absorbed.
One major application of LLLT is to treat hair loss. Also known as alopecia, hair loss can be found in every country and has unfavorable social connotations in all cultures worldwide. Male pattern hair loss, or androgenetic alopecia, accounts for 95% of alopecia in males, with 70% of American men experiencing some form of hair loss by age 35. Female hair loss, while it is often more complex in etiology, affects a similarly large portion of women worldwide, with some estimates ranging from 1:4 in the United States (25%), to over 80% of women past the age of 60 (when hormones like estrogen drop). There is no cure for male or female pattern hair loss.
Unfortunately, the list of proven medical therapies that will help even the most common causes of hair loss is a short one. In the United States, men and women can use minoxidil (2% and 5%) in both liquid and foam forms, but this medication requires twice daily application and is considered distasteful and inconvenient by many. Men have the additional benefit of being able to use the daily oral medication finasteride, which can be extremely effective. There is a widespread misunderstanding regarding its side effect profile, however, since it can transiently affect libido (2.1-3.8% incidence), which hinders its adoption. Surgical hair restoration is effective, but it is expensive, and, as a result, unavailable to many patients.
Photobiomodulation is a recent addition to the existing FDA-approved hair loss armamentarium. LLLT in the wavelengths of 614-624 nm, 668-684 nm, 751-772 nm, and 813-846 nm, has been proven to reduce inflammation in the scalp, stimulate the release of growth factors in the hair follicle, up-regulate the production of ATP (the energy source for the cell), and increase oxygen levels and blood flow via a vasodilatory effect. Devices of all sorts including combs, helmets, handheld “massager-type” units, and hoods all have gained 510K clearance to be sold with the claim that they grow hair.
Currently, none of the published studies of these devices conforms to the wavelengths of light known to produce increased cellular activity in the hair follicle, and few of them even produce light within these known wavelength ranges. Furthermore, many light therapy devices deliver light to the skin from a distance or from above the hair. Such light may be absorbed by the presence of hair follicles, thereby limiting the available dose. Even if hair is not initially present, if hair growth occurs during the use of such LLLT devices, the light therapy process will be self-limiting. For these reasons, many existing LLLT device solutions for hair growth are sub-optimal at best, and ineffective at worst. Also, dosing time and frequency recommendations vary among devices, leading to sub-optimal treatments. Another concern with conventional devices arises when the device causes heating of the targeted region of the scalp, excessive heating can decrease the results of the therapy, leading to the potential for sub-optimal dosing. Based on the above, there is room for improved systems, devices, and methods for application of LLLT therapy.